Can You Replicate Your Searches?

A comment at PubMed raises the question of replicating reported literature searches:

From the comment:

Mellisa Rethlefsen

I thank the authors of this Cochrane review for providing their search strategies in the document Appendix. Upon trying to reproduce the Ovid MEDLINE search strategy, we came across several errors. It is unclear whether these are transcription errors or represent actual errors in the performed search strategy, though likely the former.

For instance, in line 39, the search is “tumour bed boost.sh.kw.ti.ab” [quotes not in original]. The correct syntax would be “tumour bed boost.sh,kw,ti,ab” [no quotes]. The same is true for line 41, where the commas are replaced with periods.

In line 42, the search is “Breast Neoplasms /rt.sh” [quotes not in original]. It is not entirely clear what the authors meant here, but likely they meant to search the MeSH heading Breast Neoplasms with the subheading radiotherapy. If that is the case, the search should have been “Breast Neoplasms/rt” [no quotes].

In lines 43 and 44, it appears as though the authors were trying to search for the MeSH term “Radiotherapy, Conformal” with two different subheadings, which they spell out and end with a subject heading field search (i.e., Radiotherapy, Conformal/adverse events.sh). In Ovid syntax, however, the correct search syntax would be “Radiotherapy, Conformal/ae” [no quotes] without the subheading spelled out and without the extraneous .sh.

In line 47, there is another minor error, again with .sh being extraneously added to the search term “Radiotherapy/” [quotes not in original].

Though these errors are minor and are highly likely to be transcription errors, when attempting to replicate this search, each of these lines produces an error in Ovid. If a searcher is unaware of how to fix these problems, the search becomes unreplicable. Because the search could not have been completed as published, it is unlikely this was actually how the search was performed; however, it is a good case study to examine how even small details matter greatly for reproducibility in search strategies.

A great reminder that replication of searches is a non-trivial task and that search engines are literal to the point of idiocy.

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